Hunting For Webshell Activity

---
name: hunting-for-webshell-activity
description: Use when hunt for web shell deployments on internet-facing servers by
  analyzing file creation in web directories, suspicious process spawning from web
  servers, and anomalous HTTP patterns. Use when hunting for web shell deployments
  on internet-facing servers by analyzing.
domain: cybersecurity
tags:
- threat-hunting
- mitre-attack
- webshell
- persistence
- web-server
- t1505
- proactive-detection
subdomain: threat-hunting
version: '1.0'
author: oyi77
license: Apache-2.0
d3fend_techniques:
- Executable Denylisting
- Execution Isolation
- File Metadata Consistency Validation
- Restore Access
- Process Termination
nist_csf:
- DE.CM-01
- DE.AE-02
- DE.AE-07
- ID.RA-05
category: cybersecurity
---

# Hunting For Webshell Activity

## Overview

Cybersecurity skill for hunting for webshell activity. Follows industry best practices and security standards.

## When to Use

**Trigger phrases:**
- "hunting for webshell activity"
- "When proactively hunting for indicators of hunting for webshell activity in the"
- "After threat intelligence indicates active campaigns using these techniques"
- "During incident response to scope compromise related to these techniques"


- When proactively hunting for indicators of hunting for webshell activity in the environment
- After threat intelligence indicates active campaigns using these techniques
- During incident response to scope compromise related to these techniques
- When EDR or SIEM alerts trigger on related indicators
- During periodic security assessments and purple team exercises


## When NOT to Use

- When you lack proper authorization for testing
- For production systems without change management
- When the task requires legal or compliance expertise beyond technical scope


## Prerequisites

- EDR platform with process and network telemetry (CrowdStrike, MDE, SentinelOne)
- SIEM with relevant log data ingested (Splunk, Elastic, Sentinel)
- Sysmon deployed with comprehensive configuration
- Windows Security Event Log forwarding enabled
- Threat intelligence feeds for IOC correlation

## Workflow

```python
# Example: IOC detection
import re

IOC_PATTERNS = {
    "ip": r"\b(?:\d{1,3}\.){3}\d{1,3}\b",
    "domain": r"\b[a-z0-9-]+\.[a-z]{2,}\b",
    "hash_md5": r"\b[a-f0-9]{32}\b",
    "hash_sha256": r"\b[a-f0-9]{64}\b",
}

def extract_iocs(text: str) -> dict:
    return {k: re.findall(v, text) for k, v in IOC_PATTERNS.items()}
```

1. **Define Detection Scope** — Identify the specific  techniques or indicators to hunt. Map to MITRE ATT&CK tactics/techniques where applicable.
2. **Collect Baseline Data** — Gather historical logs and establish normal behavior patterns for .
3. **Build Detection Queries** — Write webshell activity queries targeting  indicators. Use platform-specific query language for optimal performance.
4. **Execute Hunts** — Run queries against the collected data, starting with broad filters and narrowing down.
5. **Triage Results** — Investigate alerts, filter false positives, and validate findings against known-good behavior.
6. **Document Findings** — Record confirmed detections, IOCs, and affected systems. Update detection rules based on findings.

## Tools

- **webshell activity** — Primary tool for this skill
- **SIEM Platform** — Central log aggregation and query execution
- **Sigma Rules** — Vendor-agnostic detection rule format
- **MITRE ATT&CK Navigator** — Technique mapping and coverage analysis


## Process

1. **Reconnaissance** — Gather target information, identify attack surface, enumerate services
1. **Analysis/Exploitation** — Execute the technique, analyze results, document findings
1. **Reporting** — Document IOCs, write findings, provide remediation recommendations

## Verification

- [ ] All  procedures executed completely and documented
- [ ] Findings validated against multiple data sources
- [ ] False positives identified and filtered
- [ ] Results documented with evidence and timestamps
- [ ] Recommendations provided with risk-based prioritization

## Anti-Rationalization Table

| Rationalization | Reality |
|---|---|
| "We are too small to be targeted" | Automated attacks target everyone. Size does not matter. |
| "Security slows us down" | A breach slows you down 100x more. Build security in from the start. |
| "We will fix it after launch" | Vulnerabilities in production are exploited within hours. Fix before deploy. |